The mayor of Santorini has called for calm after the island was struck by “intense” tremors for a fourth day in a row.

Schools remained shut and additional flights were scheduled on Monday to help people leave the popular holiday destination as quakes, some with a magnitude above 4, rattled Santorini every few minutes.

Tremors have been recorded between the volcanic islands of Santorini and Amorgos in the Aegean Sea since Friday.

Rock and debris were filmed cascading down the island’s steep cliffs on Monday. Disaster response units have been deployed on the ground as a precaution.